Evaluate the effect of salicylic acid and ascorbic acid on agronomic and antioxidant activities of Sunflower in water deficit conditions

Abstract

To evaluate the effect of salicylic acid and ascorbic acid foliar application on a number of agronomic and antioxidant activities of sunflower, an experiment was conducted at research farm of Mahabad city, locted in the south of West Azerbaijan Province, Iran during 2016-2018 cropping seasons. The experiment was laid out as a split-plot design based on a completely randomized block design with three replications. Irrigation regimes (irrigation after 60 mm and irrigation after 120 mm evaporation from class A pan respectively) were established as main plots and the foliar applications of ascorbic acid (control, 50 and 100 ppm) and salicylic acid (control, 100 and 200 ppm) were the sub-plots. In the present study, the highest amount of proline content and activity of antioxidant enzymes was recorded under water deficit conditions and foliar application of 100 ppm salicylic acid. Applying salicylic acid increased grain yield under both normal irrigation and water deficit conditions. Also, the highest proline content and activity of antioxidant enzymes were under the treatment of water deficit and application of 50 ppm ascorbic acid. The results showed no significant difference between the combined foliar application of salicylic acid and ascorbic acid in terms of grain yield and oil percentage with their separate application. Therefore, simultaneous use of these two substances under normal irrigation and water deficit conditions was not economical and not recommended.